On Fri, Aug 10, 2018 at 11:21:14AM -0700, Tadeusz Struk wrote:
> On 08/10/2018 10:43 AM, Jarkko Sakkinen wrote:
> >> +static struct workqueue_struct *tpm_dev_wq;
> > A naming contradiction with tpm_common_read() and tpm_common_write(). To
> > sort that up I would suggest adding a commit to the patch set that
> > renames these functions as tpm_dev_common_read() and
> > tpm_dev_common_write() and use the name tpm_common_dev_wq here.
> >
>
> Currently we have: tpm_open(), tpm_write(), tpm_release() in tpm-dev.c
> tpmrm_open(), tpmrm_read(), tpmrm_write(), tpmrm_release() in tpmrm-dev.c
> tpm_common_open(), tpm_common_read(), tpm_common_write(), tpm_common_release() in tpm-dev-common.c
>
> I think that's pretty consistent. Do you want me to rename all of them to tpm_dev_*()?
> I don't see any value in doing this. What about if I just rename:
> tpm_dev_wq_lock to tpm_common_wq_lock, and tpm_dev_wq to tpm_common_wq?
That is good enough. At least it is consistent.
> >> +static DEFINE_MUTEX(tpm_dev_wq_lock);
> > This is an unacceptable way to do it, Rather add:
> >
> > int __init tpm_dev_common_init(void)
> > {
> > tpm_dev_common_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
> > if (!tpm_dev_common_wq)
> > return -ENOMEM;
> >
> > return 0;
> > }
> >
> > and call this in the driver initialization.
> >
> That was the way it was implemented in v1 https://patchwork.kernel.org/patch/10442125/
>
> See: static int __init tpm_dev_common_init(void)
>
> and the feedback I got from Jason was:
>
> "I wonder if it is worth creating this when the first file is
> opened.. Lots of systems have TPMs but few use the userspace.."
>
> so I changed this to allocate the WQ on first open. I think it makes sense,
> but I leave it to you to decide.
Without a question I would go with tpm_common_init() for stability (one
less point of failure in open) and simplicity (no need for a locking
scheme).
> Tadeusz,
> --
> Tadeusz
/Jarkko
